It's genuinely possible that the title is all you need; I was tempted to write nothing further.  Feel free to take ten seconds and see if it's already clicked.  If not, read on.

When something is in your literal blind spot, it's invisible to you, but your brain stitches together everything else around it to make you think that you're seeing a complete picture.

Reality:

Blind spot:

Perception:

We often use "blind spot" as a metaphor to gesture toward things we are unaware of, while also being at least somewhat unaware of our unawareness—we know that something fishy is going on, but we can't quite get our eyes on it.

e.g. "I think I might have a blind spot when it comes to status dynamics."

The thing about status dynamics, though, is that they aren't in one spot.  There isn't a whole world that is being fully and accurately perceived, except for one blank space that's being glossed over.

Instead, what's usually going on (at least in my experience) is that the person can see everything, but there's some crucial component of the picture that they are unable to process or comprehend.

What this looks like, in practice, is an inability to distinguish two things which are very, very different, à la red-green color blindness:

"Look," says Alexis.  "Look at the beautiful contrast."

Blake hesitates.  "...you mean between the trees and the sky?"

Being (metaphorically) color-blind to something can be deeply frustrating.  You keep pushing the X button, and very different things keep happening.

e.g. you are learning to play a Formula 1 racing simulator, and it feels like you did exactly the same thing on exactly the same curve both times, but one time you spun out and crashed and the other time you smoothly navigated right through.

e.g. you are repeating back to the native French speaker exactly the sounds she said to you, and sometimes getting nods and smiles and other times getting sympathetic winces.

e.g. you asked your romantic partner what you should have said, instead, to avoid this huge disagreement, and the words they wished you'd said are literally equivalent in meaning, that's the exact same sentiment, what the hell is going on, here?

It's straightforwardly analogous to being literally color-blind, where you might try on one t-shirt, and hear snickers and giggles and see people trying not to laugh, but then you swap it out for a t-shirt that is almost exactly the same shade, you can barely even tell them apart, and suddenly everybody's all encouragement and compliments.

They're the exact same shirt!  They're practically indistinguishable!

Yes—to you.  But other people make distinctions you do not.  Whether because they've got slightly different physical or mental structures, or because they've spent a lot of time focusing on a domain and developed substantial sensitivity to it, or because they came from a subculture where those distinctions were obvious and omnipresent.

(And you make distinctions that are invisible to them, most likely!  That seem to them capricious and arbitrary, if not entirely made up!)

Trigger: Notice that someone is being weirdly intense about a meaningless distinction.

Action: Ask "if they were perceiving some facet of reality that I am insensitive to (rather than just making mountains out of molehills), what might it be?"

Trigger: Notice that someone (including you) just used the term "blind spot."

Action: Ask what the thing allegedly "in" the "blind spot" is, and whether it is local, or distributed/omnipresent.

Trigger: Notice that someone is continually ignoring your gestures toward an Extremely Important Thing™, or that they keep failing to successfully extrapolate even though you've laid out a bunch of individual examples and the trend should be obvious by now.

Action: Imagine that they are color-blind to this property, and consider what other proxies or algorithms you might hand them, that are not dependent on directly perceiving the Extremely Important Thing™.

For calibration: mostly-replacing my mental category of "blind spot" with "color-blind" has been one of the ten most useful shifts of my last three years, by virtue of a) giving me a much better starting point for navigating inferential gaps, and b) somehow causing me to be more empathetic?  ...I suppose because if the problem is a blind spot, then if they just shift their focus a little, they should see the thing, dammit, whereas if I model them as simply lacking the ability to perceive (even if only because they haven't practiced enough in this domain yet) it suddenly seems much less their-fault if merely shifting their focus doesn't fix it.

YMMV, but at the risk of being too clever by half: there really is a useful distinction, here.